Composite structure rotor for axial flux electric machine
Patent Information
- Application Number
- FR2020007913
- Authority / Receiving Office
- FR · FR
- Patent Type
- Patents
- Current Assignee / Owner
- Filing Date
- 2020-07-27
- Publication Date
- 2025-02-14
- Estimated Expiration
- 2040-07-27
Smart Images
Figure 00000009_0000 
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Abstract
Description
Title of the invention: Rotor with composite structure for axial flux electric machine
[0001] The present invention relates, in the field of axial flux electrical machines, to a rotor with a composite structure, as well as an axial flux electrical machine comprising such a rotor.
[0002] Such rotors are already known, intended for application in automobiles, in the traction of an electric or hybrid vehicle, or other. These rotors use composite materials to overcome the risk of overheating of the permanent magnet rotor, which could disrupt the magnetic fluxes and restrict performance. Thus, the permanent magnets can be embedded in a composite material or arranged on a support made of a composite material, possibly in housings provided for this purpose, which makes it possible to reduce the mass and therefore the phenomenon of overheating, with however the disadvantage of lower resistance due to the stresses due to the force of inertia and centrifugal force.
[0003] To overcome this problem, it has been proposed to equip the periphery of the rotor with a hoop, made of fiber-reinforced composite material, to contain the magnets subjected to centrifugal force.
[0004] For the purpose of improvement, and more particularly to address the problems of resistance generated by the increase in rotation speeds, document FR 3 027 468 proposes a rotor equipped with a cylindrical hoop consisting of a winding of unidirectional fibers and arranged to exert a prestressing force on the underlying magnet poles, and capable of compressing the underlying magnet poles in the direction of the shaft element by means of inserts arranged between the magnet poles and the shaft element.
[0005] If the rotor thus designed made it possible to resolve the problems posed at the time, it is now outdated in view of the desired rotation speeds, at which the hoop, despite its low mass, is subjected to centrifugal force.
[0006] The aim of the present invention is to propose a rotor with a composite structure for an axial flux electric machine, which offers increased resistance making it possible to meet new market requirements.
[0007] The rotor with a composite structure according to the invention, for axial flux electrical machines comprising at least one stator and one rotor secured to a shaft to be driven in rotation, it is shaped as a disc and comprises a plurality of permanent magnets carried by a support made of composite material secured to said shaft to be driven and consisting of a fiber-reinforced matrix, is characterized in that said support made of composite material comprises peripheral housings each capable of containing a magnet, attachment means distributed peripherally around the passage of said shaft, and in that each of the housings is delimited at least laterally by two radial or substantially radial elements and on the side of the periphery of the rotor by a wall connecting said two radial or substantially radial elements and against which a magnet bears by its outer edge, and in that said radial or substantially radial elements, of one or more housings, neighboring or not, as well as the walls which connect two by two said radial or substantially radial elements, for one or more housings, neighboring or not, are derived from the winding of unidirectional continuous fibers passing between said magnets, on the outer edge thereof, as well as on each of said attachment means.
[0008] The outer walls retain the magnets through the radial or substantially radial elements retained by the attachment means.
[0009] The radial or substantially radial orientation of the lateral elements depends on the shape of the magnets, which are not systematically in the form of circular sectors, but can take various forms.
[0010] According to an additional characteristic of the rotor according to the invention, it comprises a hoop consisting of a hoop resulting from a winding of unidirectional continuous fibers.
[0011] The hoop may not be necessary, but when the rotor according to the invention has one, it can be of reduced size.
[0012] According to another additional characteristic of the rotor according to the invention, each housing is delimited by a frame resulting from a single winding operation, and independent of other frames.
[0013] According to another additional characteristic of the rotor according to the invention, one magnet out of two is housed in a frame, while each of the other magnets is housed between two frames arranged opposite each other, while trapping between their radial or substantially radial elements one of the radial or substantially radial elements of each of the adjacent intercalated frames.
[0014] According to another additional characteristic of the rotor according to the invention, one housing out of two is delimited by a frame resulting from a single winding operation and is associated with a hooking means, while all the other housings result from the winding of continuous unidirectional fibers, passing between the magnets and on the hooking means associated with the frames.
[0015] According to another additional characteristic of the rotor according to the invention, the attachment means consist of pins with axes parallel to that of passage of the shaft to be driven, and distributed coaxially.
[0016] According to another additional feature of the rotor, the pins are connected through of a piece resulting from a winding of continuous unidirectional fibers, passing from one to the other.
[0017] According to another additional characteristic of the rotor according to the invention, a set of housings is delimited by frames coming from an operation of winding continuous unidirectional fibers, passing between the magnets and on the attachment means, while the other housings are delimited by frames coming from an operation of winding continuous unidirectional fibers, passing between the magnets and on the attachment means.
[0018] According to another additional characteristic of the rotor according to the invention, all the housings are delimited by frames coming from an operation of winding continuous unidirectional fibers, passing between the magnets and on the attachment means.
[0019] The advantages and characteristics of the rotor according to the invention will emerge more clearly from the description which follows and which refers to the appended drawing, which represents several non-limiting embodiments thereof.
[0020] In the attached drawing:
[0021] [Fig-1] represents a schematic perspective view of a first mode of rea rotor design according to the invention,
[0022] [Fig.2] represents a schematic perspective view of a part of the same rotor,
[0023] [Fig.3] represents a schematic perspective view of another part of the same rotor,
[0024] [Fig.4] represents a schematic perspective view of a second mode of rea rotor design according to the invention,
[0025] [Fig.5] represents a partial schematic view of a manufacturing step of the rotor of [Fig.l],
[0026] [Fig.6] represents a partial schematic view of a manufacturing step of another embodiment of the rotor according to the invention,
[0027] [Fig.7] represents a partial schematic view of another step in the manufacture of a another embodiment of the rotor according to the invention,
[0028] [Fig.8] represents a partial schematic view of another step in the manufacture of a another embodiment of the rotor according to the invention,
[0029] [Fig.9] represents two partial schematic views A and B, of two stages of fa construction of another embodiment of the rotor according to the invention,
[0030] [Fig. 10] represents two partial schematic views A and B, of two stages of manufacturing of another embodiment of the rotor according to the invention,
[0031] [Fig. 11] represents two partial schematic views A and B, of two stages of manufacturing another embodiment of the rotor according to the invention,
[0032] [Fig. 12] a partial schematic view of a manufacturing step of another method of production of the rotor according to the invention.
[0033] Referring to [Fig. 1], a rotor of an axial flux electric machine can be seen.
[0034] In a known manner, this rotor comprises a plurality of permanent magnets 1, in this case in the form of circular sectors, arranged radially side by side, on a support 2 in the form of a disc made of a composite material, and comprising centrally a hole 20 intended for the passage and securing of a shaft, not shown, and intended to be driven in axial rotation. Furthermore, the rotor comprises peripherally a ring-shaped hoop 21.
[0035] According to the invention, the support 2 comprises, distributed around the hole 20, a multiplicity of pins 22, with axes parallel to that of the hole 20, in this case, in this first embodiment, in a number equal to that of the magnets 1, and each aligned radially with a magnet 1. Also specific to this embodiment, the pins 22 are distributed into two categories, one in two being arranged on a coaxial circle while the others are distributed on another coaxial circle.
[0036] From a manufacturing point of view, these pins 22 are, without limitation, made of ceramic.
[0037] Also referring to figures 2 and 3, parts 3 and 4 of the rotor can be seen, each intended to carry a magnet 1.
[0038] In [Fig.2], part 3 is in the form of a circular sector, comprising two rectilinear elements 30 and 31 forming an angle between them, connected in the widest part of a wall 32, and at the narrowest end, by a ring 33 intended for attachment to a pin 22. The rectilinear elements 30 and 31 delimit with the wall 32, a housing 34 of a shape suitable for receiving a magnet 1. It will be noted that in this embodiment, the housing 34 is closed on the side of the ring 33 by an intermediate wall 35 making it possible to form a frame which completely surrounds the magnet 1.
[0039] In [Fig. 3], the part 4 is also in the form of a circular sector, comprising two rectilinear elements 40 and 41 forming an angle between them, connected in the widest part of a wall 42, and at the narrowest end, by a curved segment 43 intended for attachment to a pin 22. The rectilinear elements 40 and 41 delimit with the wall 42, a housing 44 of a shape suitable for receiving a magnet 1. It will be noted that in this embodiment, the housing 44 is closed on the side of the curved segment 43 by an intermediate wall 45 making it possible to form a frame which completely surrounds the magnet 1.
[0040] As can be seen in [Fig.l], one magnet 1 out of two is arranged in the housing 34 of a part 3, while the other magnets 1 are each taken between two parts 4 in two facing housings 44, while the rectilinear elements 30 and 31 of a part 3 are each enclosed by two rectilinear elements 40 and 41 of two parts 4.
[0041] The assembly of the different parts constituting the rotor is completed by two parts 5 for holding and connecting the pins 22, each of which has a star shape due to the distribution of the pins 22 alternately on two coaxial circles, and which are arranged on either side of the rotor. The entire rotor is entirely polymerized with a resin.
[0042] From the manufacturing point of view, the parts 3 and 4 are each obtained individually by filament winding of unidirectional continuous fibers, to form a strap capable of externally enveloping the magnet 1, then polymerization in a resin. The radial rectilinear elements 30, 31, 40 and 41, in association with the walls 32 and 42 against which the outer edge 10 of the magnets 1 bears, as well as the attachment means constituted by the rings 33 and the curved segments 43, provide solid physical links between the shaft, not shown, and the magnets 1, by directly opposing the centrifugal force.
[0043] In the same way, the parts 5 for holding and connecting the pins 22 come from the filamentary winding of unidirectional continuous fibers, passing from one pin 22 to another by going around it.
[0044] Referring now to [Fig. 4], we can see another embodiment of the rotor according to the invention, in which one magnet 1 out of two is held individually by a strap in a piece 6 coming from a filamentary winding of unidirectional continuous fibers, and passing over the outer edge 10 of the magnet 1 and a pin 22, while the other magnets 1 are held collectively by a strap 7, which passes over the outer edges 10 of these magnets and over the same pins 22, so that the number of pins 22 is divided by two.
[0045] Referring now to Figures 5, 6, 7 and 8, steps of the methods of winding fibers F can be seen, for producing the support 2.
[0046] In [Fig.5], this is a process similar to that for producing the rotor in [Fig.1], where all the magnets 1 are surrounded individually, so there are as many pins 22 as there are magnets 1.
[0047] In [Fig.6], where the number of pins 22 is half that of [Fig.5], one magnet 1 out of two is individually surrounded, with the particularity that the fiber F is crossed between the magnet 1 and the pin 22, so as to create a particular housing for the magnet 1. The other magnets 1 are wrapped collectively, according to, non-limitingly, one or other of the methods reproduced in figures 7 and 8.
[0048] In [Fig.7], the winding of the other magnets 1 is in accordance with that of [Fig.4], the fiber F passing over the outer edges 10 of the magnets 1 not wound individually, and over the pins 22 already used by the individual windings, not shown.
[0049] In [Fig.8], the process is identical except that the winding on a pin 22 is preceded by the crossing of the fiber between pin 22 and magnet 1.
[0050] Referring now to figures 9, 10, 11 and 12, one can see steps of manufacturing a rotor according to the invention, by winding fibers F, in different, non-limiting cases, where the magnets 1 have shapes other than circular sectors.
[0051] In Figures 9A and 9B, as well as 12, the rotor comprises alternating magnets 11 of rectangular shape and magnets 12 of triangular shape. In Figure 9A, the magnets 11 are wound individually, while in Figure 9B the magnets 12 are wound collectively with the same fiber F.
[0052] In Figures 10A and 10B, as well as 1 1A and 1 1B, the rotor comprises alternating magnets 13 in the shape of an isosceles trapezoid, and magnets 14 in the shape of a triangular shape.
[0053] In Figure 10A, the magnets 13 are wound individually and completely, while in Figure 10B the magnets 14 are wound, also completely, collectively with the same fiber F.
[0054] In Figure 1 1A, the magnets 13 are wound collectively and completely, with the same fiber F winding around the pins 22, while in Figure 1 1B the magnets 14 are wound, also completely, and collectively in pairs with the same fiber F.
[0055] In [Fig. 12], the magnets 11 and 12 are wound with the same fiber F by winding around the pins 22.
[0056] Of course, other combinations are possible, the essential thing being to create a lattice of fibers F making it possible to create a structure capable of containing the effects of centrifugal force on the magnets.
[0057] Whatever its embodiment, the rotor according to the invention has a high resistance for a very reduced mass, and without risk of excessive heating. The rotor can be used with or without a hoop, and if it has one, it can be of reduced dimensions, and therefore of low mass.
Claims
Claims
1. Rotor with composite structure, for axial flux electrical machines comprising at least one stator and one rotor secured to a shaft to be driven in rotation, shaped as a disc and comprising a plurality of permanent magnets (1) carried by a support (2) made of composite material made integral with said shaft to be driven and consisting of a fiber-reinforced matrix, said support made of composite material comprising peripheral housings (34, 44) each containing a magnet (1, 11, 12; 13, 14), and each of the housings (34, 44) being delimited, at least laterally, by two radial (30, 31, 40, 41) or substantially radial elements and on the side of the periphery of the rotor by a wall (32, 42) connecting said two radial (30, 31, 40, 41) or substantially radial elements and against which a magnet (1, 11, 12;13, 14) by its outer edge (10), characterized in that it comprises attachment means (22) distributed peripherally around the passage (20) of said shaft, and in that said radial elements (30, 31, 40, 41) or substantially radial, of one or more housings (34, 44), neighboring or not, as well as the walls (32, 42) which connect two by two said radial elements (30, 31, 40, 41) or substantially radial, for one housing (34, 44) or more housings (34, 44) neighboring or not, are formed by windings of unidirectional continuous fibers (F) passing between said magnets (1, 11, 12; 13, 14), on the outer edge thereof, as well as on each of said attachment means (22).;
2. Rotor according to claim 1, characterized in that it comprises a hoop (2), consisting of a hoop resulting from a winding of unidirectional continuous fibers.
3. Rotor according to claim 1 or claim 2, characterized in that each housing (34, 44) is delimited by a frame (3, 4) resulting from a single winding operation, and independent of other frames.
4. Rotor according to any one of claims 1 to 3, characterized in that every other housing is delimited by a frame resulting from a single winding operation and is associated with a hooking means, while all the other housings result from the winding of continuous unidirectional fibers, passing between the magnets and on the hooking means (22) associated with the frames.
5. Rotor according to any one of claims 1 to 2, characterized in that that a set of housings is delimited by frames coming from a winding operation of continuous unidirectional fibers, passing between the magnets (14) and on the hooking means (22), while the other housings are delimited by frames coming from a winding operation of continuous unidirectional fibers, passing between the magnets (13) and on the hooking means (22).
6. Rotor according to any one of claims 1 to 2, characterized in that all the housings are delimited by frames coming from an operation of winding continuous unidirectional fibers, passing between the magnets (11, 12) and on the attachment means (22).
7. Rotor according to any one of the preceding claims, characterized in that the attachment means consist of pins (22) with axes parallel to that (20) of passage of the shaft to be driven, and distributed coaxially.
8. Rotor according to claim 7, characterized in that the pins (22) are connected through a part (5) resulting from a winding of continuous unidirectional fibers, passing from one to the other.
9. Axial flux electrical machine comprising at least one stator and one rotor secured to a shaft to be driven in rotation, characterized in that it comprises a rotor according to one of claims 1 to 8.